Preparation of MOF-5 imprinted chromium ferrite and its application in decontaminating metronidazole and penicillin G contaminated water system

Metronidazole (MZ) and penicillin G (PG) are antibiotics frequently detected in aqueous systems as pollutants. Their presence in water systems is a global challenge requiring the development of sustainable solutions for water purification. Therefore, this study synthesized and improved the adsorption performance of chromium ferrite (CrFe₂O₄) via incorporation of metal-organic framework (MOF-5) to produce CrFe₂O₄@MOF-5 composite. CrFe₂O₄@MOF-5 and CrFe₂O₄ were characterized using a series of analytical instrument. Both adsorbents exhibited a four-phase mass loss from the thermogravimetric analysis, while the Brunauer-Emmett-Teller (BET) results gave a surface area of 40.94 m² g^{- 1} for CrFe₂O₄ and 59.76 m² g^{- 1} for CrFe₂O₄@MOF-5. Interestingly, microscopical images unfolded the surfaces of CrFe₂O₄@MOF-5 and CrFe₂O₄ to be heterogeneous, while elemental surface mapping confirmed the constituent elements of CrFe₂O₄@MOF-5 and CrFe₂O₄ to be Cr, Fe, O, C and Zn. CrFe₂O₄@MOF-5 exhibited a higher affinity (91.67 mg g^{- 1}) for PG than CrFe₂O₄ (53.82 mg g^{- 1}). Similarly, the performance of CrFe₂O₄@MOF-5 was better (90.24 mg g^{- 1}) compared to CrFe₂O₄ (50.41 mg g^{- 1}) towards MZ. Both Freundlich and Langmuir isotherm may describe the removal process of MZ and PG by CrFe₂O₄@MOF-5 while sorption of MZ and PG by CrFe₂O₄ fitted best for Langmuir isotherm in a sorption mechanism involving electrostatic interaction and pore diffusion. The adsorption performance of CrFe₂O₄@MOF-5 and its regeneration capacity compared agreeably with most published adsorbents in literature. This current study showed CrFe₂O₄@MOF-5 as a potential adsorbent for decontaminating MZ and PG-polluted water systems.